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Homework Help: Tension on a wire

  1. Oct 15, 2008 #1
    Two wires are tied to the 200 g sphere shown in figure. The sphere revolves in a horiIzontal circle at a constant speed of 7.80 m/s. The diagram shows a ball with two wires, each 1 m in length with a radius of .5 m

    What is the tension in the upper wire?

    What is the tension in the lower wire?

    So, what i thought i would do was

    T + mg = mv^2/r for the tension of the upper wire and

    where T = 22.4

    T - mg = mv^2/r for the tension of the lower wire..but after doing it i am not getting the right answers

    and T = 26.3 but apparently neither are the right answers...
    Last edited: Oct 15, 2008
  2. jcsd
  3. Oct 15, 2008 #2


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    Have you properly accounted for the 30 degree angle the wires make with the vertical?
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